As electronic components are getting smaller along with the internal structures in integrated circuits, it is increasingly easier to either completely destroy or otherwise impair electronic components. In particular, many integrated circuits are highly susceptible to damage from the discharge of static electricity. Generally, electrostatic discharge (ESD) is the transfer of an electrostatic charge between bodies at different electrostatic potentials or voltages, caused by direct contact or induced by an electrostatic field. The discharge of static electricity, or ESD, has become a critical problem for the electronics industry.
Device failures resulting from ESD events are not always immediately catastrophic or apparent. Often, the device is only slightly weakened but is less able to withstand normal operating stresses. Such a weakened device may result in reliability problems. Therefore, various ESD protection circuits should be included in an integrated circuit to protect its various components.
When a transistor is impacted by an ESD pulse, the extremely high voltage of the ESD pulse can break down the transistor and can potentially cause permanent damage. Consequently, the transistors of an integrated circuit need to be protected from ESD pulses to prevent such damage.
Integrated circuits and the geometry of the transistors that make up the integrated circuits continue to be reduced in size and the transistors are arranged closer together. A transistor's physical size limits the voltage that the transistor can withstand without being damaged. Thus, breakdown voltages of transistors are lowered and currents capable of overheating components are more frequently reached by the voltages and currents induced by an ESD event.
Thus, there is a need for small ESD protection devices that can be rapidly triggered and conduct through the duration of the pulse, yet are robust against spurious effects such as false triggering.